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Poly(ethylene glycol)-block-poly(4-vinyl pyridine) as a versatile block copolym...
Rocha, Nuno; Mendes, Joana; Durães, Luisa; Maleki, Hajar; Portugal, Antonio; Geraldes, C. F. G. C.; Serra, Arménio; Coelho, JorgeThis work reports an efficient method for the preparation of aqueous dispersions of superparamagnetic iron oxide nanoparticles (SPIONs), involving the use of an amphiphilic block copolymer, poly(ethylene glycol)- block-poly(4-vinyl pyridine) (mPEG-b-P4VP). The iron oxide nanoparticles are easily and efficiently dispersed due to the strong direct interaction of the hydrophobic P4VP segments, through complexation...
Simulation of two-dimensional combustion propagation on Fe2O3/Al thermite non-h...
Brito, Paulo; Durães, Luísa; Portugal, AntónioIn previous works, a two-dimensional model was constructed and tested in a successful attempt to simulate the nonsteady radial combustion propagation on thin disk shaped samples of Fe2O3/Aluminum thermite mixtures. The main characteristics of the model can be summarized as: pseudo-homogeneous medium considering the contribution of air to simulate a porous medium; zero order, non-temperature dependent beyond a g...
Modeling and simulation of radial combustion propagation of Fe2O3/Al thermite s...
Brito, Paulo; Durães, Luísa; Portugal, AntónioIn previous works, a one-dimensional model was built to simulate the non-steady radial combustion propagation on thin disk shaped samples of Fe2O3/Aluminum thermite mixtures and was successfully tested. Now, the purpose is to extend the referred model to the more sensible two-dimensional features of the samples, maintaining the main characteristics of the previous model: zero order kinetics, conductive/radiativ...
Modeling and simulation of radial combustion propagation of Fe2O3/Al thermite s...
Brito, Paulo; Durães, Luísa; Portugal, AntónioIn previous works, a one-dimensional model was built to simulate the non-steady radial combustion propagation on thin disk shaped samples of Fe2O3/Aluminum thermite mixtures and was successfully tested. Now, the purpose is to extend the referred model to the more sensible two-dimensional features of the samples, maintaining the main characteristics of the previous model: zero order kinetics, conductive/radiativ...
Estudo da reacção entre o óxido de ferro (III) e o alumínio e avaliação do seu ...
Durães, Luísa Maria RochaTese de doutoramento em Engenharia Química (Processos Químicos) apresentada à Fac. de Ciências e Tecnologia da Univ. de Coimbra
Fe2O3/aluminum thermite reaction intermediate and final products characterization
Durães, Luísa; Costa, Benilde F.O.; Santos, Regina; Correia, António; Campos, José; Portugal, AntónioRadial combustion experiments on Fe2O3/aluminum thermite thin circular samples were conducted. A stoichiometric (Fe2O3 + 2Al) and four over aluminized mixtures were tested. The combustion products were characterized by X-ray diffraction and Mössbauer spectroscopy and the influence of Fe2O3/aluminum ratio on their composition was assessed. The main products were identified as alumina ([alpha]-Al2O3) and iron (Fe...
Simulation of Fe2O3/Al combustion: sensitivity analysis
Brito, Paulo; Durães, Luísa; Campos, José; Portugal, AntónioThe sensitivity of a one-dimensional model, built to simulate the non-steady radial combustion propagation on thin circular samples of Fe2O3/aluminium thermite mixtures, was tested in relation to its least reliable thermophysical properties and to non-homogeneities in the initial reactant media. Zero order kinetics and conductive/radiative heat transfer were considered. The model is quite insensitive to variati...
Radial Combustion Propagation in Iron(III) Oxide/Aluminum Thermite Mixtures
Durães, Luísa; Campos, José; Portugal, AntónioThe self-sustained thermite reaction between iron oxide (Fe2O3) and aluminum is a classical source of energy. In this work the radial combustion propagation on thin circular samples of stoichiometric and over aluminized Fe2O3/Al thermite mixtures is studied. The radial geometry allows an easy detection of sample heterogeneities and the observation of the combustion behavior in their vicinity. The influence of f...
Modelling and simulation of Fe2O3/aluminum thermite combustion: experimental va...
Durães, Luísa; Brito, Paulo; Campos, José; Portugal, AntónioA one-dimensional model was built to simulate the non-steady radial combustion propagation on thin circular samples of Fe2O3/Aluminum thermite mixtures. The model considers zero order kinetics and conductive/radiative heat transfer. All the properties of the system are assumed to vary with the temperature and composition during the propagation and phase transitions are also contemplated. These features, not yet...
Simulation of Fe2O3/Al combustion: sensitivity analysis
Brito, Paulo; Durães, Luísa; Campos, José; Portugal, AntónioThe self-propagating high temperature reactions, as the Fez03/AI thermite combustion, are hard to follow by experimentation due to the extreme conditions that characterize them. Hence, theoretical prediction of these processes represents a valuable guideline for experimental work. The availability of experimental results of radial combustion on disk shaped samples (Durães et aI., 2006a) has stimulated the deriv...
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